In recent years there has been a dramatic increase in the incidence of attacks on facilities and buildings by terrorists, other aggressors such as extremists, and even disgruntled employees throughout the world. Many of these attacks are directed against government facilities or other high profile locations. One of the most effective means of facility destruction is through the use of a vehicle carrying explosives. To successfully guard against such attacks a standoff distance must be created around a facility. This is accomplished by the use of a combination of active and passive barriers. Passive barriers “never” allow vehicular access to certain areas, while active barriers are utilized to control or limit vehicular access to a particular area.
Active barriers range from simple devices that damage a vehicle's tires, such as the device described in U.S. Pat. No. 4,354,771 to Dickinson, to more complex devices such as the devices described in U.S. Pat. Nos. 4,574,523 and 4,630,395 to Nasatka. These more complex devices differ from earlier designed devices, such as the device described in U.S. Pat. No. 3,963,363 to Roper, which were designed to yield vehicular traffic, thereby acting more as a traffic guide than a traffic control. Current vehicular barrier designs seek to stop and immobilize unauthorized vehicles that collide with the barrier.
Since the Sep. 11, 2000 attacks on the U.S., a significant number of facilities are seeking active barrier solutions. The owners of such facilities, as well as the architectural design community, are demanding a more aesthetically pleasing active barrier solution. Facility owners and the general public do not want the streets to appear like a war zone with ominous looking barrier designs.
One of the biggest concerns with current barrier design is the use of hydraulic systems for the activation of the barrier, such as the barrier device described in U.S. Pat. No. 4,818,136 to Nasatka et al. and U.S. Pat. No. RE33,201 to Dickinson. These hydraulic systems must be routinely maintained or the barriers will eventually fail to operate. A typical hydraulic system must have its filters changed on a monthly basis or on a quarterly basis if the barrier is rarely used. The fluid in the hydraulic systems must also be changed at regular intervals similar to the oil in an ordinary car.
It is estimated that more than half of barrier system failures are related to the hydraulic system. A major source of failure in these hydraulic systems is related to the hoses and fittings. Even with the use of pneumatic systems in place of hydraulic systems, similar problems exist with hoses and fittings and system reliability. Another common failure point in hydraulic systems is that most hydraulic systems are designed to include solenoid valves, flow control valves, and accumulators that are used to control the movement and speed of movement of the barrier. These solenoid valves tend to fail often and are sensitive to the condition of the hydraulic fluid. The flow control valves are also sensitive to the condition of the fluid, while the accumulators have to be pre-charged to a certain operating pressure and must maintain that pressure. Small leaks or failures in the accumulators result in the barrier system not functioning properly. Typical hydraulic systems may contain fifteen gallons of fluid and in many cases more than double such amount. Additionally, typical hydraulic systems require a large hydraulic tank to act as a reservoir for the hydraulic fluid. In the event of a hydraulic system failure, such lost fluid creates an environmental hazard. Many of the systems installed today do not properly contain the fluid and, therefore, lost fluid will adversely impact the surrounding environment when a hydraulic system failure occurs.
One of the challenges with barriers designed to withstand the crash of a vehicle is designing a foundation to hold the barrier in place during impact. Current art solves this problem by providing a large in-ground barrier foundation, such as the device described in U.S. Pat. No 4,627,763 to Roemer et al., or by providing very large inertia blocks on the surface of the roadway as described in U.S. Pat. No. 6,382,869 to Dickinson.
Providing a large in-ground foundation is not always possible due to underground utilities or building structures. Further, the large inertia blocks on the surface of a roadway often are too large and limit the flow of traffic in the roadway. Many variations of the in-ground barrier are in use today. One of the biggest challenges is that the barrier and the foundation are essentially one unit, thereby making installation difficult at best. Another issue is that the local authorities, such as the Department of Transportation, may require that the barrier not be permanently attached to the road and be able to be easily removed from the road in the future, if so desired. None of the current art sufficiently solves these problems.
Another challenge with barrier design deals with the ability of the plate to withstand the crash of a vehicle. To overcome the large forces involved in a crash, current art utilizes reinforced and/or multi-layered plates to create a honeycomb effect and, thus, increase the robustness of the barrier plate. These designs have several disadvantages including, but not limited to, heavy construction, significant cost, and the need to go below the road surface to prevent the large structure from having to be above the roadway.
What is needed is an aesthetically pleasing vehicle barrier control device having a two-part barrier system, composed of an in-ground frame and a bolt down barrier, and a plate with a bend near the free end, that can utilize a self-contained motor and actuator, reversible motor and pump, and variable speed motor control. It is to such a device that the present invention is primarily directed.